While primary doors on dwellings provide the principal means or protection against weather and intruders, it has become customary to position a storm door or screen door adjacent to the exterior side of the primary door. Such storm door can protect the primary door from rain, snow, and other harsh elements, thereby prolonging its useful life. Likewise, a storm door or screen door, as the case may be, can allow sunshine and breezes to enter the home when the primary door is left in the open position.
A latch bolt assembly is required on such storm doors and screen doors to secure them in their closed position. Traditionally, such latch bolt has entailed a simple assembly of a pivotable latching arm for engaging a stop located on the door jamb wherein the latching arm is operated by a latch operator on the interior side of the door and a push button and plunger operated from the exterior side of the door. See, e.g., U.S. Pat. No. 4,864,835 issued to Wartian. However, a consumer desire has developed in recent years within the market place for more elegant and substantial storm doors and screen doors that more closely approximate primary doors. In particular, this includes the use of mortise live bolts that are recessed within the interior of the storm door or screen door, and are operated on one side by a rotatable door knob or lever. Such mortise live bolts frequently entail a live bolt retractor and cam sleeve combination that translates the rotary movement of the door knob or lever via a spindle to linear movement to retract the live bolt from a mating hole in the doorjamb to allow the door to be opened. A spring biases the live bolt back to its extended position when external force is removed from the door knob or lever to secure the door in its closed position. See, e.g., U.S. Pat. No. 4,671,089 issued to Fleming et al., and U.S. Pat. No. 6,536,248 issued to Fan.
Because home owners may choose to leave their primary door open on a nice day, an increasing need has arisen for secure locking mechanisms on the storm door or screen door. Such locking mechanisms can also provide a secondary lock for security purposes. The type of locking mechanism traditionally provided with push-button/latch operator door latch assemblies was insufficiently robust. Therefore, the storm door industry is increasingly resorting to deadbolts recessed within the door that are actuated by a key-operated cam. Various deadbolt cam assembly structures are disclosed in U.S. Pat. No. 4,864,835 issued to Wartian and U.S. Pat. No. 6,302,456 issued to Errani, as well as U.S. Published Application No. 2003/0106350A1 filed by Char et al. Such cam assemblies, however, often require a complicated arrangement of interconnecting or interlocking parts for translating the key rotation to linear movement of the deadbolt.
Several other problems arise from the live bolt and deadbolt configuration of latch bolt assemblies commonly used on storm doors or screen doors. First, such live bolts are typically actuated in one direction only—namely by a lever that is rotated downward. The deadbolt is usually positioned below the handle. This means that these latch bolt assemblies must be installed by the manufacturer for custom-designed doors for right vs. left-hand hinge applications. But, this requirement increases inventory costs for the storm door manufacturers and retailers. Alternatively, the pre-installed live bolt may be reoriented, or rotated, by the installer to accommodate right vs. left-hand hinge applications. This requires, however, removal of the mortise plate from the door edge followed by removal, reorientation, and reassembly of the live bolt, handles, spindle, and other associated parts by the installer, which increases installation time and cost at the job site. Simply put, the storm door or screen door cannot be flipped over to convert between right and left-handed hinge applications because these traditional mortise live bolts do not allow for bi-directional handle actuation, and the lock is not symmetrical. Once flipped, the door handle would only function in the upward direction, and the deadbolt lock would be positioned above the handle.
Another limiting constraint on traditional storm doors is the inability to use knobs for handles, because the live bolt actuation is not bi-directional. Yet another difficulty is caused by the rectangular cross section of the deadbolt which requires precise mortising of the mated opening in the doorjamb for receiving the deadbolt. Again, this increases time and cost for the installer. Finally, the structural design of most deadbolt cam operators does not resist the application of excessive force to the end of the deadbolt protrusion that forces the deadbolt to its neutral or retracted position. Therefore, such deadbolts do not function as “true deadbolts” which creates potential security concerns. Likewise, many handle cams in latch bolt assemblies used within the industry cannot accommodate catastrophic loads applied to the handle, which can cause safety problems.
Therefore, it would be advantageous to provide a latch bolt assembly for a door containing bi-directional handle action that can accommodate either knob or lever action, tandem deadbolt actuation symmetrically positioned above and below the live bolt to accommodate vertical inversion during installation of the door for right vs. left-hand hinge application without the need for cumbersome live bolt reorientation, and circular deadbolts that permit simple and quick drilling of the mating holes in the door jamb without the need for precise mortising. Such live bolt and deadbolt components could be preassembled by the manufacturer to enable simple and quick installation of the door at the job site. Moreover, it would be desirable to provide a live bolt assembly that withstands the application of catastrophic forces on the handles, and deadbolts that operate as true deadbolts.